1. Field of the Invention
The present invention relates generally to stair module support systems. More particularly, the present invention relates to a stair module support system including a flexible engagement between the stair module and the support posts that permits quick and simple deployment of the support posts without requiring tools.
2. Description of Related Art
Conventional installation procedures of prefabricated modular stair units have been time-consuming and tedious and, therefore, expensive. Additionally, the stability against shifting or settling of the installed stair module have been unsatisfactory.
One common method used to install a modular stair involves the construction of columns or piers under the stair module. The columns generally include two or more concrete blocks and/or bricks which rest on a concrete footer. The columns abut the underside of one or more steps on the stair module. It is important and difficult to construct a footer that is level and which resists settling and/or misalignment. Conventional support columns are required to be built on the footer from the ground up to provide support for the stair module. Additionally, shims are required to attain proper leveling of the stair module. This leveling is particularly important when the stairs form a portion of a contiguous wall in a swimming pool.
Another conventional method for supporting modular stairs uses a truss system. For example, U channel fixtures may be secured to a collar and to the front base of a riser of the modular stairs. The fixtures are then used to attach a truss support to the stair module. This system requires an elaborate and difficult to assemble truss system which requires multiple threaded fasteners.
Each of the above-described conventional stair support systems require extensive assembly and installation procedures. Thereby, adding to the expense of installing a modular stair unit.
In 1986, Quaker Plastic Corporation patented a unique stair module support and leveling construction as disclosed in U.S. Pat. No. 4,589,237 the disclosure of which is incorporated herein in its entirety. The stair support system includes support posts attached to the underside of each stair tread using a channel. The post is secured to the channel using rigid bolts or pins extending through downwardly extending side walls from the channel and through the support post. This arrangement facilitates installation of the stair module by allowing the support to be installed from the top, i.e. the underside of the stair module, down to the ground. Shoes are provided at the bottom of, and secured to the post in conjunction with a reinforcing rod. The stair module, with the underneath supporting post assembly secured to the stair module, is lowered in place and leveled. The bottom of the post, the shoes and the reinforcing rod are then buried in concrete to provide a footing.
Subsequently, in 1989, Quaker Plastic Corporation patented a system to impart controlled rigidity to the flexure of a molded plastic structural module as disclosed in U.S. Pat. No. 4,873,802, the disclosure of which is incorporated herein in its entirety.
The invention is an improvement on the unique stair module support system developed by the Quaker Plastic Corporation. An exemplary embodiment of the invention has a flexible engagement between the support posts and a channel or pad secured to the underside of the stair module. The engagement flexes to allow the support post to be rotated from a stored position to a deployed position. In an exemplary embodiment, the engagement may include a flexible connection which flexes to provide a tension to the post such that the post is biased against the underside of the stair module. Biasing the post against the stair module may establish the relative angle between the underside of the stair module and the post.
In an exemplary embodiment of the invention, the stair module support system is assembled at a manufacturing facility such that the support posts are stored in the channels for shipping and storage. Quaker Plastic Corporation has a trademark for the system which provides the ability to provide for easy shipping and storage. The trademark is LOCK DOWN BLEACHER SYSTEM(trademark). The flexible engagement is substantially stress free in the post storage configuration. At the installation site, the post is rotated from the stored position in the channel into the deployed position. The flexible engagement enables the post to rotate from the stored position to the deployed position and may maintain a tension on the post to maintain the post in its deployed position.
Each post may include a shoe attached to the bottom end of the post. The shoe includes hooks that may interact with corresponding barbs on the walls of the channel to latch the shoe and attached post into the stored configuration. The hooks of the shoe easily unlatch from the channel for deployment of the post. The shoe may also include a flexible engagement to the post in a manner similar to the flexible engagement between the post and the channel attached to the underside of the stair module. The engagement may also flex to bias the post into the shoe, in this way, the relative angular orientation of the shoe to the post may be established.
The invention is directed particularly to a support system for stair modules or xe2x80x9cshells,xe2x80x9d primarily those that include a plurality of, i.e. two or more, steps. In an exemplary embodiment of the invention, the system supports the stair module from the top down to the support level, as distinguished from a system in which the support comprises building up from the ground to the underside of the stair module. In an exemplary embodiment, support plates or pads are used which are formed integrally on, bonded to or otherwise secured on the underside of the steps or stair module. The vertical support is secured to the support pad through extensions or protrusions which are formed on the support pad. By this arrangement of connecting the support post to the pad, through the extensions formed on the pad, any load, such as that of the water and/or persons placed on the stairs, is distributed evenly across the area of the pad and then to the support post which may be similarly connected to the pad and to the ground or substrate. This arrangement has the effect of allowing the equal distribution of load through the pad and into the post through direct contact with the top/end surface of the support post.
As described above, a shoe may be connected to the bottom of the support post using a flexible engagement, however, the support post may also have a reinforcing rod (rerod). The shoe, rerod and support post may be encapsulated in poured concrete as in a footer. The system affords a greater surface area on which to distribute any weight placed on the stairs. The stair shell or module support system, thus, includes an arrangement in which the stairs are supported by support posts in conjunction with support pads that are bonded to, or mechanically attached. etc. the underside of the steps.
In a first exemplary embodiment of the flexible engagement, the rigidizing channel has side walls which are provided with holes through which a flexible fastener passes through corresponding holes in upper end of the support posts. Wile the holes on the pads may be substantially aligned with the holes in the vertical posts when the posts are in the stored position, the two sets of holes may be slightly offset to provide a strain on the flexible fastener which acts in tension and/or shear to bias the post upward into firm contact with the underside of the pad and to solidly hold the post in a predetermined angular orientation with the pad.
In this first exemplary embodiment of the invention, the flexible fastener may be an elongate shaft having a head, a barrel, a barrel catch and an installation tail. The installation tail may be inserted through the holes in the side walls of the channel and the hole in the top end of the support post. The distal end of the installation tail, extending completely through this assembly, may then be pulled to bring the barrel catch through both holes in the side walls of the channel and the hole in the top of the support post. The tail may be pulled using a rotary tool that grasps the end of the installation tail and rotates to wrap the installation tool around the rotary tool. Once the barrel catch extends completely through, the installation tail may be removed. Thereby, leaving behind a flexible fastener having a head at a proximal end, a flexible barrel shaft extending through the channel and the support post and a barrel catch at a distal end.
The lower end of the post may similarly be connected to and rest upon a shoe placed on the ground or substrate. The shoes are so constructed as to suitably support the vertical posts and may have a construction similar to the support plates having vertical protrusions, side walls or extensions and holes therethrough which receive another flexible fastener to secure the post to the shoe. In the deployed position, holes in the shoes may be offset from the corresponding holes in the vertical post such that the flexible fastener may be strained. The strain causes the flexible fastener to act in tension and/or shear to bias the post into firm contact with the top of the shoe and to solidly hold the post in a predetermined angular orientation with the shoe. The holes in the shoes and the posts, however, may substantially align when the post is in the stored position in the shoe.
Alternatively, the shoe may be connected to the post using a flexible connection which allows the base of the shoe to be spaced a short distance from the lower end of the post so that the shoe has the ability to find its own relative angle between itself and the post. The angle between the shoe and the post may then be determined by the relative angle between the post and the ground surface upon which the shoe rests. This configuration enables the shoe to obtain a good footing with ground that may not be entirely level.
The lower ends of the posts may also have additional holes to receive a rerod horizontally disposed and in spaced relation and, preferably, at an angle substantially parallel to the flexible fastener in the shoe. The support shoes and rerod are suitably buried in concrete for greater strength. To enhance load support, additional posts may be added to engage the underside of additional steps of the stair module. Rerods may then be inserted through the vertical posts. In an alternative embodiment, the rerod may be positioned at an angle other than substantially parallel to the flexible fastener in the shoe, as for example, in a substantially perpendicular relative angle.
In a second exemplary embodiment of the invention, the flexible engagement between the post and the rigidizing channel may be provided by a flexible end of the post. For example, in this exemplary embodiment, the flexible engagement is established with a threaded fastener, such as a bolt, extending through both walls of the rigidizing channel and through a hole near the top of the post. Thus, while the threaded fastener is substantially rigid in the hole near the top of the post, the top end of the post is flexible such that as the post is rotated from a stored position to the deployed position, the top end of the post deforms to allow the rotation.
In a third exemplary embodiment of the invention, the flexible engagement may be provided using a flexible bushing. A flexible bushing is positioned in holes on both sides of the support post near the top end of the support post. Each of the flexible bushings may then have a hole that substantially aligns with the hole in the other. A threaded fastener extends through the holes in the walls of the rigidizing channel and through both holes in the flexible bushings. As the support post is rotated from the stored position to the deployed position, the flexible bushings flex to allow the support post to rotate. The flexible bushings may also slightly bias the post into the rigidizing channel to establish the relative angle between the post and the channel.
In a fourth exemplary embodiment of the invention, the flexible engagement between the support post and the rigidizing channel may be established using a flexible insert in the top end of the tubular post. The flexible insert may be a plug that inserts into the top end of post. The insert provides the flexibility between the top of the post and the channel. The insert is connected to the top end of the post using a fastener which extends through the side walls of the rigidizing channel, through holes in both sides of the post and through the flexible insert. The flexible insert may have a series of concentric rings and may be made from any flexible material. The flexible insert deforms in response to the channel to allow the post to rotate into the deployed position.
The invention provides several benefits over previous stair support systems. For example, the stair support system may be entirely manufactured, installed and assembled at the factory, thereby minimizing the risk of lost parts and incorrect assembly. The entire unit may be assembled and prepared for storage and shipping in a compact package. Once at the installation site, the posts merely need to be rotated into the deployed position much like the legs on a card table without the use of tools. No assembly is required at the installation site for the LOCK DOWN BLEACHER SYSTEM(trademark). The deployment of the stair support system also does not require any special tools for installation. The stored posts also accommodate stacking of multiple units for shipping. Additionally, once the posts are deployed, they maintain their deployed position and do not flop around like conventional stair support systems.
These and other features and advantages of this invention are described in or are apparent from the following detailed description of exemplary embodiments.